Process of making phosphatic slag and iron.



HERMANN MEHNER, QF VELTEN, GERMANY.

' No Drawing.

Specification of Letters Patent.

Application filed May 17, 1910. Serial No. 561,872.

.IROCESS OF MAKING PHOSPHATIG SLAG AND IRON.

Patented Dec. 6, 1910.

To all whom it may concern:

Be it known that I, HERMANN MEHNER, a citizen of the German Empire, and resident of VeltenQin-the-Mark, Germany,

chemist, have invented certain new and use- 7 ful Improvements in Processes of Making Phosphatic Slag and Iron, of whichthe fol lowing is a specification My invention relates to a process of manu facturing phosphoric compounds suitable for use as fertilizers, and iron, preferably by running a blast-furnace with phosphate slags insteadof with silicate slags. In prac-' ticing this preferred embodiment of my invention, I' heat iron ores in a blast-furnace together with tricalcium-phosphate or compounds in such proportion that a slag rich in tetra-calcium phosphate is formed, and separate the manure-forming slag from the iron phosphid, or iron rich in phosphid, and thereafter treat the iron material in a suitable furnace with iron oxygen compounds, in presence of basic additions, and again separate the slag-from the metal, this slag also being suitable for manuring purposes.

In this process, a part ofthe phosphoric acid contained in the tricalcium-phosphate is reduced under the conditions existing in the blast-furnace, so that a slag containing tetracalcium phosphate is formed at the same time with iron phosphid or iron rich in iron *phosphid. The iron phosphid contains latent heat in the form of chemical energy and may be used for carrylng out heat-requiring processes. Especially may such hemical energy be advantageously used for reducing iron-oxygen compounds in suitable,

' lime may be used, in which case a slag is' preferably open hearth furnaces, as abovementloned with addition of sultable baslc materlals. As a basic material, for instance,

formed which is rich in tetra-calcium phosphate. In order to obtain a slag in which the content of tetra-calcium phosphate is. as high as possible, it is advisable to make" the required addition'bf lime in two portions. In this instance the first portion of' lime result-s in the formation of a slagwhich is very rich in tetra-calcium phosphate. This slag may be drawn oif before a further portion of lime is added. The slag formed from the further portion of lime becomes less rich in phosphate of calcium and may be used as addition to the ore introduced into the blast-furnace. dolomite or magnesite may be used.

Instead of lime, burnt The combination of, the above described blast-furnace process with the open hearthfurnace process results in a very economi-.

calmethod of reducing iron ores.

As to the relative proportions of the materials to be treated, the reactions. which take place must be considered. These reactions occurring in the blast-furnace can be seen from the following equations, assuming that chemically pure substances are used and thatan ironore is to be treated which from a chemical point of View consists of Fe,(),:

These three diiferent reactions practically occur simultaneously. From these equations it appears that, for every 232 pounds of Fe Q, contained in the iron ore to be treated, 1240 pounds of 4(CaO) P O rnay betaken, together with a quantity of carbon suflicient for reduction. The reduction can practically be eifected with less carbon than conforms to the above equations, because the carbon oxid (CO) acts likewise as a reducing agent. Of course more or less iron'ore may be taken according to the degree of.

phosphoriz ation of the iron which is to be obtained; Further, greater or less amounts of silica and impurities enter the blast-furnace with the ores and other materials, which are not shown by the equations.

I Relative to the treatment of the iron phosphid produced by the new blast-furnace process: The reactions taking place may be seen from the following equation, given as an example, and the proportions of the materials may be calculated therefrom 4Fe P -+5Fe O +l6CaO= l I 27Ee+4(CaO),P O,-,.

Iii-order to abstract from the iron phosphid the whole of the phosphorus contained therein, it is practically necessary to use an Thereforeithis process may be carried out as above stated in such way that at first only the greater part of the phosphorus is removed from the iron phosphid by a comparatively small amount of lime, and thereafter the last portion by a comparatively great amount of lime. The amount of phosphorus in'the first and second slags largely materials and on the skill of the worker and manager.

Instead of converting the tricalcium-phos- I phate intothe tetra-calcium phosphate by using it as addition to iron ores in a blastfurnace, the phosphoric acid in the tricalcium-phosphate may be reduced by treating the phosphate with reducing agents in pres ence of ores of other metals than iron, or with free metals of suitable kind, either in a blast-furnace or in other suitable furnaces or ovens. Eventually the reducing action may be effected without a phosphorus binding re-agent being present. Furthermore, the iron phosphid obtained by the reduction of phosphoric acid contained in phosphates in the presence of free or chemically bound iron may be used, not only in an open hearth process for reducing iron ores but also used for recovering scrap iron, which may be melted in considerable quantities by coniparatively small quantities of iron phosphid, on account of the latent energy accumulated therein.

What I claim is:

1. In the rocess of manufacturing a phosphatic-slag ertilizer, the improvement which comprises treating tricalciumphosphate-containing material so as to reduce a part of the phosphoric acid contained therein and form a phosphatic slag consisting substantially of tetra-calcium hosphate, and separating the product of t e -phosphoric-acid-reduction from the fertilizer-formingresidue.

2. In the rocess of manufacturing a phosphatic-slag ertilizer, the improvement which comprises heatingtricalcium-phosphate-containmg material 1n resence of carbon so as to partially dephospiioriz'e the phosphate and convert it into a phosphate slag consisting substantially of tetra-calcium phosphate.

'3. 'In the rocess of manufacturing a phosphatic-slag ertilizer, the improvement which comprises treating tricalcium-phosphate-c0n taining material in presence of carbon and a metal-containing material, so as to reduce a part of the phosphoric acid contained in said tricalcium-phosphate-containing material, forming thereby a phosphatic slag consisting substantially of tetra-calcium phosphate, and binding the freed phosphorus to the metal, and separating the slag from the phosphorus-containing metal. 1 4. In the rocess of manufacturing a phosph atic-slag ertilizer, the improvement which comprises treating tricalcium-phosphate-coniron soas to reduce a part of the phosphoric acid contained in said tricalcinm-phosphatccontaining material, forming thereby a phosphatic slag consisting substantially of tetracalcium phosphate, and separating, the same from the formed iron-phosphorus compound.

5. In the rocess of manufacturing a phosphatic-slag1 ertilizer the improvement which comprises eating tricalcium-phosphate-containing material in admii ture with metallic ores and carbon so as to partly dephos horize the tricalcium-phosphate material, erming thereby from the phosphate a phosphatic slag consisting substantially of tetra'calcium phosphate, and separating the same f om the product of reduction of the metallic ores.

6. In the process. of manufacturing a phosphatic-slag fertilizer, the improvement which com rises heating tricalcium-phosphate-containing material in admixture with iron ores and carbon so as to partly dephosphorize the tricalcium-phosphate material, forming thereby from the phosphate a phosphatic slag consisting substantially of tetra-calcium phosphate, and separating the same from the product of reduction of the iron ores.

7. The process of making phosphatic slag and iron, which consists in heating tricalcium-phosphate-containing material in admixture with iron ores and carbon so as. to partly dephosphorize the phosphate, forming thereby a fertilizer slag, separating said slag'from the iron-phosphid-containing ma- :taining material in presence of carbon and terial resulting from the reaction of the In testimon whereof, I. aiiix my signature two witnesses.

in presence 0 HERMANN MEHNER;

lVitnesses HENRY HASPER,

WOLDEMAR HAUPT. 

